Create cpl_multiproc.h

/**********************************************************************
 * $Id: cpl_multiproc.h,v 1.10 2006/01/25 19:52:25 fwarmerdam Exp $
 *
 * Project:  CPL - Common Portability Library
 * Purpose:  CPL Multi-Threading, and process handling portability functions.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
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 * Copyright (c) 2002, Frank Warmerdam
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
 * DEALINGS IN THE SOFTWARE.
 **********************************************************************
 *
 * $Log: cpl_multiproc.h,v $
 * Revision 1.10  2006/01/25 19:52:25  fwarmerdam
 * default to avoiding as much mutex overhead as opposed if MUTEX_NONE defined
 *
 * Revision 1.9  2005/08/24 22:19:27  fwarmerdam
 * added CPLCleanupTLS
 *
 * Revision 1.8  2005/07/08 18:17:52  fwarmerdam
 * complete TLS implementation for win32
 *
 * Revision 1.7  2005/07/08 14:35:26  fwarmerdam
 * preliminary TLS support
 *
 * Revision 1.6  2005/05/23 06:39:49  fwarmerdam
 * added CPLMutexHolder stuff
 *
 * Revision 1.5  2005/05/20 19:19:00  fwarmerdam
 * added CPLCreateOrAcquireMutex()
 *
 * Revision 1.4  2005/04/26 20:52:10  fwarmerdam
 * use a typedef type for thread mains (for Sun port)
 *
 * Revision 1.3  2003/04/23 04:36:55  warmerda
 * pthreads based implementation
 *
 * Revision 1.2  2002/05/24 04:09:24  warmerda
 * fixed CPL_DLL declarations
 *
 * Revision 1.1  2002/05/24 04:01:01  warmerda
 * New
 *
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